Telephone



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E. M, HARRISON. TELEPHONE.

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(No Model.) I 4 Sheets-Sheet 3. E. M. HARRISON. TELEPHONE. No. 499,108. Patented 1111 1893.

(No Model.) 4 Sheets-Sheet 4. E. M. HARRISON. TELEPHONE.

No. 499,108. Patented June 6, 1893.

UNHE STATES PATENT OFFIcn.

EDWARD M. HARRISON, OF FORT SMITH, ARKANSAS.

T E L E P H O N E SPECIFICATION forming part of Letters Patent No. 499,108, dated June 6, 1893.

Application filed May 31, 1892. Serial No. 34,836. (N model.)

.To all whom it may concern:

Be it known that I, EDWARD M. HARRISON, a citizen of the United States, residing at Fort Smith, in the county of Sebastian and State of Arkansas, have invented certain new and useful Improvements in Electric Telephones; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same. a

This invention relates to electric telephones and embraces improvements in the various devices constituting a complete apparatus or telephone, as will be hereinafter specifically described and pointed out in connection with the accompanying drawings.

The objects of my invention are, first, to provide improvements in the transmitter by means of which the resistance to the flow of the galvanic current is reduced to the minimum, and by which the diaphragm may be adjusted, so as to increase or decrease the pressure of the hammer electrode upon the anvil or pendent electrodes according to the requirements of the case; second, to provide an improved faradic electric generator or induction coil, whereby the secondary coil is reinforced and its intensity increased and improved results secured; third, to provide a new and improved electro-phonetic motor or receiver, whereby the volume of the sonorous sounds and vibrations, and also its quality, are increased, the tones and quality being made soft and clear; fourth, to provide an improved magneto electric generator, whereby alternating currents of increased strength are produced, so as to overcome the resistance of the line, thereby producing a sharp, clear ring at the call bell; fifth, to provide a new and improved magneto ringer, whereby the construction is simplified and the bell hammer is strongly actuated by the current; sixth, to provide a new and improved lightning arrester for protecting the telephone against lightning or any strong currents of electricity; and also to provide certain de-,

tails of construction for connecting my electrical devices one with another to form an improved operative telephone, as hereinafter described.

The matter constituting my invention will be defined in the claims.

I will now describe my invention in detail by reference to the accompanying drawings, in which- Figure 1 represents a front elevation of the telephone box or case with the doors thrown open, showing the different devices in position. Fig. 2 represents a vertical transverse section through the case (looking to the left) and the internal devices with the mouth piece and transmitter omitted from the front door. Fig. 3 represents a front elevation of the case with the doors closed. Fig. 4 represents atop plan view of the phonetic motor or receiver having the top cover removed. Fig. 5 represents a longitudinal section thereof. Figs. 6 and 7 represent plan views respectively of the short and long diaphragms of the receiver. Fig. 8 represents a longitudinal section, on en larged scale, of theinduction coil. Fig. 9 represents a vertical section (looking to the right) through the case, and showing the magneto electric generator and transmitter in position.

Fig. 10 represents a vertical section throughthe case and generator taken on a plane at right angles to the plane of section in Figs. 2 and9. Fig. 11 represents a plan view of the wooden phonetic transmitter diaphragm, provided with the transverse wooden bridge and carbon rail or hammer electrode. Fig. 12 represents a vertical section of the phonetic transmitter as applied to the door or one of the walls of the telephone case. Fig. 13 represents a front view of the transmitter frame. Fig. 14. represents a vertical section of the phonetic transmitter, showing a slight modification in the means for supporting the diaphragm. Fig. 15 represents a transverse sec tion of the phonetic transmitter. Fig. 16 represents a transverse section of the ringer taken on a plane at right angles to the plane of sec tion in Fig. 2, and looking toward the left in said Fig. 2. Fig. 17 represents avertical section, on enlarged scale, of the phonetic motor or receiver similar to the view shown in Fig. 5. Figs. 18 and 19 represent respectively a vertical section and a top plan view of a modified form of receiver. Figs. 20 and 21 represent respectively top plan views of the short and long diaphragms of the modified receiver.

The inclosing telephone box or case, A, is composed of two side walls, A, A ,andasuitable bottom, A applied to a back board D, which projects up a short distance above the top of the case for the purpose of receiving the lightning arrester and binding post of the line wires, as shown in Fig. 3. The upper front corners of side walls, A, A are cut off diagonally, to provide for arranging the upper door B, in an inclined position, as shown making electrical connections when the door O is closed. The front edge of door B, is formed with a rabbet, 1), adapted to receive the upper angular edge of the lower door 0, and make a tight joint therewith for excluding dust, as shown in Fig. 2. The door B, having been shut down, the door 0, when closed and locked, will hold the upper door in place. As will be seen in Figs. 1 and 2, the ringer T, is applied to the under side of door B, and the phonetic transmitter is secured to the inside of door 0, so that when such doors are thrown open the parts may be readily inspected and cleaned or repaired.

My phonetic transmitter, mounted in a suitable frame, is secured to the inside of door 0, over its mouth piece, 0, as shown in Figs. 1, 9, and 12.

The transmitter frame, E, is composed of the parallel side bars E, the, cross bars E, at. top and bottom, and the pivoted bottom bar, E The bar, E, is pivotally connected at its ends near its lower edge, to the side bars, E, so that its upper edge can be adj usted out and in by means of the set screw, e"", asshown in Figs. 9 and 12. This adjustable bar or lever serves for adjusting the diaphragm out or in, so as to increase or decrease the pressure of the hammer electrode upon the pendent anvil electrodes so as to facilitate the instantaneous return of the anvil electrodes, if they should leave the hammer electrode too far according to the different requirements. To the upper ends of the side bars, E, I secure the two brackets, e, e, which areperforated transversely for receiving and holding the pivotal rod, e, which supports the pendent electrodes G, as shown in Figs. 1, 9 and 12. These electrodes are provided with transverse holes near their upper ends, through which is passed the pivotal rod, 6', which rests at its ends in the brackets e. On. one of the brackets 6, next to the upper hinge c, I secure a washer, e", for making electrical connection with said hinge and thence to the induction coil; and on the side bar E, of the frame, adjacent to the lower hinge c, I secure a second washer e, for making electrical connection through the hinge to the binding post as, of battery X. The frame is secured to door 0 by means of screws. The diaphragm F, of the phonetic transmitter is composed of a single piece of thin wood or its equivalent, about the twenty-fourth of an inch thick, and of a peculiar elliptical shape, having elongated portions, f, f, at the ends of its long axis or at the arches of the ellipse, as shown in Figs. 1 and 11, and it rests on rubber cushions, h, h, which permit its free and an instantaneous vibration. The diaphragm is lightly sup.- ported in its frame, with its elongated ends, fif, resting on the rubber cushions, h, h, by means of the fiat springs h, at top and bottom, which springs are secured at their ends to the frame, as shown in Figs. land 13. Instead of supporting the diaphragm by means of the fiat springs, I may support it by means of flexible rubber cushions, h", which are attached at one end to the frame, and at the other end to the diaphragm at top and bottom of the frame, as shown in Fig. 14, and I have found this latter arrangement to give satisfactory results in practice.

A transverse wooden bridge, f, is secured to about the middle portion of the diaphragm, and has outwardly flaring ends, as shown in Fig. 15. In practice, the bridge F, is about two and one half inches long, at its top surface and only about one and one-half inches long at its bottom surface for the purpose of better protecting the transverse carbon rod or hammer electrode, f", which is applied to its upper surface. The transverse electrode, f is made triangular in cross section, preferably in the form of an equilateral triangle, and is glued at one of its fiat surfaces to the wooden bridge, f, so that one of its sharp edges shall be presented to the flat surfaces of the pendent anvil electrodes, thereby providing a clean, sharp contact edge, which prevents accumulation of dust and dirt.

As shown in Figs. 12 and 15, the pendent electrodes G, are made flat on one side at or near their lower ends 9 for the purpose of increasing their contact surfaces against the the sharp edge of the transverse hammer electrode f". The effect of this construction and of the triangular transverse electrode is to reduce the resistance to the flow of the galvanic current and produce clear and perfect vibrations in the receiver, free from overtones. The main object which I have in providing a sharp contact edge on the transverseham mer electrodes f", is that I desire to make the contact between such electrodes and the fiat surfaces of the pendent electrodes G, as perfect in continuity as possible, for the reason that this reduces theresistance between the contacting parts to its very minimum. This cannot be done with too curved contact surfaces, as used in my Patent N 0. 476,200; nor could it be done with too flat contact surfaces, for the reason that an atom of dust or other non-conducting material which might get between the too flat or curved contacts, would adhere thereto, breaking the circuit and destroying the instantaneous flow of the galvanic current, but, if the hammer electrode is made with a sharp contact edge, it will, of its own force, push the atom of obstruction to one side, thereby keeping the con-' tact perfect. Furthermore it is well known in mechanics, that the contact surfaces of too curved or flat carbons cannot be brought nearer together than about one .two-hund reth of an inch when under slight pressure. Where there is virtually no pressure, as in my pendent electrodes, the contact is not near so close; but, by making the contact edge of the transverse hammer electrode f sharp, the continuity is too all intents and purposes perfect; at least, they are within one four-thousandth of an inch of making perfect contact. Besides, too loose, curved or flat contact electrodes produce current-lag, the very thing that I avoid in my combination phonetic transmitter. It is very important to overcome this current-lag in a complete long or short distance instrument, such as herein described.

The object in having the anvil pendent electrodes flat on one side at or near their lower ends is two-fold:the fiat surfaces increase the length of contact surface of the sharp transverse hammer electrode and also prevents defacing or nicking of the sharp conact edge by the constant concussions, produced by the inward and outward motions of the hammer electrode against the pendent or anvil electrodes.

By making the diaphragm of my transmitter independent of the anvil electrodes, the brackets and the frame,I am enabled to give the maximum motion to the lower ends of the anvil electrodes and the minimum motion to the upper ends thereofavhereby improved results are secured, as pointed out in my Patent No. 476,200.

The carbon electrodes, G, hang from their pivotal rod 6, nearly perpendicular, with their lower ends lightly resting on the transverse electrodes, f, making a loose connection between such parts, which can therefore be easily putinto motion by the least vibration of the diaphragm. By means of the adjustable bar,E, of the frame and its adjusting screw, e, the lower end of the diaphragm may be raised or lowered, thereby increasing or decreasing the gravity of the carbon electrodes, G, according to the requirements under different conditions.

The air put in motion on entering the case, through the conical mou th-piece escapes freely above and below the lateral arches of the elliptical diaphragm, thereby obviating the rebounds of air which would otherwise occur and which produce over tones and interfere with the instantaneous vibrationspf the diaphragm.

My induction coil H, is preferably located in the upper part of the case and secured to the back board D, as shown in Figs. 1 and 2. The coil, (Fig. 8) is composed of the usual spool I, having a central longitudinal opening filled with soft iron rods, 6, and the Wooden core is first wrapped with the usual primary coil K, the end Wire of which is carried out through the ends of the spool and afterward applied to the induction coil, as below explained. Around the primary coil, there is applied a wrapping of paper or thin card board, after which there is applied the secondary coil, L, containing, as a new and additional feature, the insulated flat iron rings, i", which divide it into sections for the purpose of reinforcing said said secondary coil. One, two, or any desired number of such rings may be used for increasing the intensity of the secondary coil. When wrapping this coil,

one section is preferably wrapped to the full thickness, and then there is placedagainst such section a flat iron ring 71; then the next section is wrapped to its full thickness, and another ring, 1', placed against it, and so on until the required number of sections are wrapped, filling the spool. The sectional coils of the secondary coil are connected together, either by means of a continuous wire being used, or the ends of the wires at adjacent sections, are united over the rings, 71. After the completion of the secondary coil, with its rings in position, a wrapping of paper or card board is applied, and then one end of the primary coil K, is carried around from the first wrapping and is coiled or wound in a single layer K, around the secondary coil, and then its free end is connected, through the transmitter, with the battery. The other end of the primary coil, K, is connected with the battery through the switch. The induction coil is finally covered with binding cloth or other suitable material.

My electric phonetic motor or receiver, is illustrated in Figs. 4 to 7, inclusive, and is best shown on enlarged scale in Fig. 17. For ordinary use, the receiver is preferably made with an elongated handle, as shown in Figs. 4, 5, and 17. The case of the receiver, M, is composed of wood or hard rubber, and is preferably provided with a double bottom, m, m and a cover, M, with car piece, m. Internally the case is provided with two electro magnetic coils, N, N, secured to the side and at the opposite ends of the permanent steel bar magnet O, which bar is clamped to the bottom of the case, by means of the wooden strip, 0, and screws passing through it into the bottom piece on. The adj usting-screw, 0, is passed through the bottom of the case and bears against the permanent magnet O, for adjusting it and the electro magnets. The top cover, M, and ear piece, m are slightly recessed at their inner surfaces for forming, in connection, with the long diaphragm, n, a shallow soundingohambero. Theearpiece, m, is preferably recessed deeper than the remaining portion of the cover, as shown in Fig. 17.

In the construction of my diaphragm, I provide two ferro-type plates,one an octagonal or circular diaphragm plat-en (Fig. 7) having a long narrow projection extending the full length of the receiver case and resting at its edges on the top of the case below the cover,

' Figs. 4 and 5, and being in contact at its elongated end with the electro magnet, N, at the south end of the permanent magnet; and the other plate, it, placed at the receiverend of the case below the ear piece and in contact with the electro magnet N, at the north end of the permanent magnet. The plate, 07., is provided with two or more circumferential projections, n, as shown in Figs. 6 and 20, by means of which it is supported on the top edges of the walls of the case, (as indicated by dotted lines in Figs. 4 and 19) therebyleaving its edges free to vibrate. The two plates,

' 'n. and n, are insulated one from the other by a piece of soft tissue paper, 71.", silk, or other suitable material. The object of the long diaphragm n, is to increase the intensity of the vibrations. By means of the inner diaphragm, having free edges as described, the sonorous sounds and vibrations are increased and by means of the above described arrangement of the outer long diaphragm and the inner diaphragm with insulating material between them, the objectionable over tones and metallic sounds usually present, or usually occurring in the receiver, are practically done away with and much more satisfactory results secured. The tones and quality are made soft and clear. The construction and arrangement of the different parts of the receiver are important features of my invention.

The wooden clamping strip 0, in Figs. 4, 5 and 17, is grooved on its sides, as indicated by the dotted lines for the passage of the connecting wires. An eye or ring 6' is secured to the elongated end of the case for hanging the receiver upon the hook of the telephone switch bar P, as shown in Fig. 1.

In order to provide an elect-ro-phonetic motor or receiver which shall be more compact and convenient in use, I construct it in the short or circular form illustrated in Figs. 18 to 21 inclusive. This form is more particularly adapted for use of attendants at the switch-board, in fire alarm boxes, &c. In this form of receiver the permanent steel magnet is bent at right angles, invthe form of an L, forming a horizontal leg 0, and a vertical leg, 0, and to the end of the horizontal leg are applied the two electro-magnets, N, N, and the end of leg 0 is brought into contact with the outer or long plate, 01., of the diaphragm, which plate is clamped between the edges of the case and the cover M. The inner plate, at, of the diaphragm is constructed and applied as heretofore described, and between the two plates is placed the insulating material n. Binding posts 6 and 7 are secured to the case of the receiver and are connected internally to the electro magnetic coils.

The switch, P, j, 70,1, the form which I preferably use, has been described and claimed in my Patent No. 476,200. It consists of a long metal bar, P, having at its outer end a hook, p, and at its inner end a thin horizontal piece of hard tempered metal, 19''; said bar being pivoted to the socket, q, of the escutcheon Q. The upper part of the escutcheon is elongated in the form of a tube, q, and its lower end is formed with a socket g, which extends through the wall of the case, as shown in Fig. 1. The stiff spiral spring, d, is inserted in tube, q, and secured at the top by binding screw, d, and is connected at its lower end with switch-bar, P,serving to pull the hook end of said bar up when the weight is removed therefrom, as shown by dotted lines. The switch springs, is, Z, represent the terminals of the primary and line circuits. If the receiver is removed from the hook, p, the spiral spring, d, will raise the bar P, thereby shifting the metal contact piece 10', from the upper spring, j, to the two lower springs 70, Z, thus cutting out the magneto bell ringer, T, and connecting into circuit the battery X, to

the transmitter E, and the receiver M, to the line wire.

My new form of magneto electric generator is illustrated in Figs. 2, 9 and 10, and is composed of two pairs of horseshoe magnets, R, R, which rest at their lower ends upon the brass bottom plate P" In each pair one of the magnets is arranged within the other, and the two pairs are separated a short distance apart, as shown in Figs. 2 and 9. At the lower endsand innersides of theinterior magnets are attached the small plates or projections, r, 0', having curved upper edges, arranged nearly in line with the arc, which would be described by the armatures u, at the ends of the electromagnets. The two brass side plates, P, P, are placed adjacent to the sides of the horseshoe magnets and serve for supporting the upper andlower shafts s and U. The upper power shaft, 8, is provided with alarge toothed gear wheel 5', which meshes with the pinion, u, and also with a spiral spring, 8, which bears against the two side plates, as shown in Fig. 10. Shaft s, is also provided with a crank or handle, 8. By means of the spiral spring, 5, the shaft 5, may be pushed in, so that the spur-wheel 8 shall leave the shunt contacts. The lower shaft U, is supported in bearings in the brass plates, P, P", and is provided at its outer end with pinion u, and at its inner end with the commutator V. At about the middle portion of shaft U, there are secured the four spools or electro-magnets to, having at their outer ends the armatures, u, made of soft iron. The spools are arranged upon the shaft radially, or perpendicularly thereto, as shown in Figs. 2 and 9. In constructing the commutator, the shaft U, is formed with four radial ribs, u', so that in cross section it is in the shape of a cross, and the spaces between such ribs are filled with four brass segments 0, having between them and the iron shaft and ribs any suitable insulating material, as indicated by the heavy black lines in Figs. 9 and 10. Two brushes w, w, formed IIO of brass or copper strips, and having their inner ends curved are secured in convenient position to bear upon the commutator, as best shown in Figs. 9 and 10.

The electro magnets are wound in the usual manner withfine insulated copper wire. One end of the wire on each spool is attached to shaft U, and the otherend of the wire of each spool is attached to a separate brass segment, '0, of the commutator for producing the alternating currents. The brushes in contact with the commutator, take 01f the electric current and conduct it to the ringer T. This form of generator is very simple in construction, can be made at a small cost, and is very effective in operation. The generator is in electrical connection with the ringer, which will next be described.

The ringer, T, is preferably applied to the under side of door B, and the bells are applied to the outside of such door. The horseshoe magnet, W, is secured by one of its legs or poles, to door B, by means of the soft iron bar 25, (Fig. 16) and the screws, 1;. At each end of bar If, there is secured by the screws, 1;, an angle piece or bracket, 25, of soft iron, and the horizontal portions of such brackets are provided with end slots, t", (Fig. 1) by means of which they may be adjusted outor in for adjusting the electro magnets, g, g. To the downwardly extending portions of brackets, t, are connected the two inwardly projecting magnets or spools, g, g. The two electro-magnets project inward between the poles of the permanent magnet and at right angles to its longitudinal axis. The armature W, is pivotally supported on a bracket, 10", attached to the lower pole or leg of the horseshoe magnet, and such armature projects up between the two electro-magnets, as shown in Figs. 2and 16. i A rod, 'y, is attached to the upper end of the armature, w", and projects up through an opening formed in bar i, one.

leg of the magnet and door B, and is provided at its upper end with a hammer, y, which is arranged between two bells, Y, as shown in Fig. 16. The bells, Y, are connected to the door, B, in the usual manner. The electro magnets divide the polarity of the permanent magnet into right angle sections for increasing the force of the hammer against the bells, as the alternating currents flow into and out of said electro magnetic coils.

My lightning arrester X, illustrated in Figs. 2 and 3, is applied to the back-board, D, of the telephone case, just above the bells. It is composed of three brass plates, 5, b, provided with deep notches, y,y, and a diamond-shaped central plate, a", all of which plates are secured by means of screws to the back board D. The central diamond shaped plate is termed the ground-plate. Two binding-posts,'a, a, for the line wires, pass through the outer ends of plates, 1), b", and are secured in the back board D. A third binding post, a, is made fast to the center of plate 0, for attachment of the ground wire.. Four holes or sockets, 1, 2, 3, 4., are made in the plates, 1), b, and c, and back board, as shown in Fig. 3,-for insertion of a metallic plug for changing the direction of the current, and cutting outany one or all of the three connecting telephones. A. metallic plug,inserted at hole 1, cutsout this telephone; if inserted at 2, it cuts out the left hand telephone; if inserted at 3, it cuts out the right hand telephone; and if inserted at 4, it cuts out all three telephones.

The lightning arrester, as is well known, serves to protect the internal devices of the telephone from lightning or any strong current of electricity. 1

In addition to the above-described lightning arrester, I provide a secretlightning arrester, Z, (Fig. 1) which is secured to the inner edge of the cover B, between the hinges, a, a, and it consists of two small metallic strips, .2, z,one of which is pointed and the other of which is notched, the pointed end being placed within the notched end, as shown in Fig. 1. The metallic strips, z, a, are in contact with the hinges,a, and serve to cut out the ringer in case of lightning. The flat curved springs, 19', connected with one leaf of each of the hinges, serve to perfect the electrical connections when door B is closed, as shown in Fig. 2. i

When the instantaneous alternating intermittent flashes of induced electricity from the induction coil H, reach the receiver, they pass through the north and south coils N, N, and, therefore, exert an opposite magnetic force upon the para-magnetic ferro type plates or diaphragms n,n',in front of them, which plates are held in a permanent state of attraction.

by contact of the electro-magnet N. When these instantaneous alternating flashes of electricity in the coils N, N, are in such a direction as to oppose the. atomic polarity of the para-magnetic plates, they will cause each atom in the plates to reverse its polarity, thereby giving off sounds at each north and south electrical movement of the atoms similar to those given to thetransmitter. The succession of alternating filashes of electricity produce instantaneous starts and stopsyor alternating north and south vibrations in the ferro-type plates, at, n, precisely similar to the instantaneous starts and stops or vibrations of the phonetic diaphragm F, in the transmitter, so that the sounds emitted by the receiving plates, 77., n, are similar to those sounds actuating the transmitter. From this it will be seen that the transmitter acts as'a generator converting the instantaneous starts, stops, and vibrations, or mechanical energy of the diaphragm F into'galvanic or electrical energy through the primary cur rent and circuit, while the receiver acts as an electro-phonetic motor, converting the alternating electrical energy of the main or secondary line into mechanical vibrations or instantaneous north and south electro atomic polarities of the ferro-type plates at, n. The tones or sounds, it will be noticed, are not transmitted from one point to another.

Having described my invention, what I claim, and desire to secure by Letters Patent, 1s

1. In aphonetic transmitter, the diaphragm, having a transverse bridge and a carbon electrode, provided with a sharp contact edge, and secured to said bridge for making a perfect contact with the pendent anvil electrodes, substantially as described.

2. In a phonetic transmitter, the carbon hammer electrode, having a sharp contact edge, and secured to the diaphragm, in combination with pendent electrodes, having flat contact surfaces at their lower ends, substantially as described.

3. In a phonetic transmitter, the frame provided with an adjustable transverse bar, in combination with the diaphragm, resting at one end upon said bar, substantially as de scribed.

4. In combination with the transmitter frame, the elliptical diaphragm, and supporting cushions, h", 72/, connected at one of their ends to the diaphragm and at their other ends to the frame, substantially as described.

5. In an induction coil, the secondary coil, composed of sections of coils and interposed soft iron rings, for increasing the intensity of the secondary coil, substantially as described.

6. In an induction coil, the secondary coil, composed of sections of coils and interposed soft iron rings for increasing the intensity of the secondary coil, in combination with the primary coil wound on the spool inside of the secondary and also on the outside of the secondary for evenly distributing the galvanic current, substantially as described.

7. In an electro-phonetic motor or receiver, a long permanent magnet, having an electromagnet at each end thereof in combination with a long diaphragm plate, extending the full length of the receiver case, and in contact at one end with one of the electro-magnets, substantially as described.

8. In an electro-phonetic motor or receiver, a long permanent magnet having an electromagnet at each end thereof in combination with a para-magnetic diaphragm plate of octagonal or circular form and having a long narrow projection extending the full length of the receiver case, its projected end being in contact with the electro-magnet N, at the lower end of the case, substantially as described.

9. In an electro-phonetic motor or receiver, the combination with the permanent magnet connected thereto and an electro magnet of a diaphragm plate of uniform thickness, having circumferential projections, by which it is supported in the case, leaving its circumferential edges free to vibrate, substantially as described.

10. In combination with the permanent magnet, a long diaphragm plate, in contact with one pole of said magnet, a second diaphragm plate, provided with circumferential projections by which it is supported in the case, leaving its edges free to vibrate, and an electro-magnet between said plate and the permanent magnet,substantially as described.

10. In combination with the permanent magnet and one or more electro magnets, a long diaphragm plate, a short diaphragm plate and a layer of insulating material between them, substantially as described.

12. In a receiver, the combination with the permanent magnet and one or more electromagnets, of a long diaphragm plate, extending from end to end of the case, a cover, and a long shallow sounding chamber between said long plate and cover, substantially as described.

13. In a magneto electro generator, the horse shoe magnets, the transverseiron shaft, carrying the electro magnets between the legs of said horse-shoe magnet, and having one end formed with radial ribs, between which are inserted segments of diamagnetic metal, and insulating material forming the commutator, substantially as described.

14:. In a magneto ringer, the horse-shoe magnet, having attached to one of its legs or poles, a soft iron bar, in combination with the two electro magnets, supported by said bar transversely between the two poles of the horse shoe magnet, and an armature connected to the other pole of the horse shoe magnet and passing between the two electromagnets substantially as described.

15. In a magneto ringer, the horse shoe magnet, having attached to one of its legs or poles, a soft iron bar, adjustable slotted brackets attached to said bar and carrying the two electro magnets for adjusting the said magnets, substantially as described.

16. In combination with the telephone case, a lightning arrester composed of two outer plates, having notches,g y, at their adjacent ends and an interior diamond-shaped plate arranged in said notches, and havinga binding post for the ground wire, substantially as described.

17. In combination with the telephone case, a lightning arrester for cutting out the ringer, composed of two metallic strips, respectively notched and pointed, secured to the hinges and located between the edge of the door and case, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

EDWARD M. HARRISON.

Witnesses:

WM. A. EASTERDAY, L. V. BEALE. 

